Molecules ranging in size from phospholipids to surface antigens move laterally through cell membranes, facts conveniently represented by the fluid mosaic model formulated by Singer and Nicholson, Science, 175, 720-731 (1972). Molecular mobility rises with increasing membrane fluidity [cf/ Shimshick et al. J. Supramol. Biol., 1, 285-289 (1973); Michaelson et al., Biochemistry, 12, 2637-2645 (1973); and Pagano et al., Science, 181, 557-559 (1973)], which, in turn, is related to the proportion of unsaturated alkanoic acid residues present in both natural [Fox et al., Membrane Molecular Biology (1972)] and bilayer model [Sackman et al., J. Am. Chem. Soc., 94, 4482-4498 (1972)] membranes. There is scattered evidence in the literature showing that assembly of membrane transport systems [Tsukagoshi et al., Biochemistry, 12, 2816-2829 (1973)] and the membrane functions of transport [Schairer et al., J. Mol. Biol., 44, 209-214 (1969); Esfahani et al., Proc. Natl. Acad. Sci. U.S., 68, 3180-3184 ( 1971); and Linden et al., Proc. Natl. Acad. Sci. U.S. 70, 2271-2275 (1973)] and permeability [de Kruyf et al., Biochim. Biophys. Acta, 298, 479-499 (1973)] are augmented with increased membrane fluidity [McConnell et al., Biochem. Biophys. Res. Commun., 47, 273-281 (1972)]. Logic therefore dictates that agents which increase membrane fluidity might produce useful and interesting biological changes.